1. Field of the Invention
The present invention relates to a paper feeding stand on which a recording apparatus such as a copying machine or the like is mounted and which is equipped with a paper feeding mechanism for feeding paper to the recording apparatus.
2. Description of the Prior Art
In one type of stand on which a copying machine is mounted, a paper feeding mechanism is provided as a supplemental feature for a copying machine, in addition to the paper feeding mechanism provided within the copying machine. Such a stand is so constructed that the paper is fed from the paper cassette installed in the stand to the paper entry provided at the bottom of the copying machine.
In such a stand, the paper is taken up one by one in a longitudinal direction from the horizontally mounted paper cassette by means of the take-up roller so provided as to press contact the paper. Then, the paper is transported vertically by way of a guide plate or the like toward the paper entry of the copying machine. The paper is then fed into the copying machine by means of a pair of intermediate rollers provided in the paper exit on the top of the stand at the position facing the paper entry of the copying machine till it stops at the pair of resist rollers located near the photosensitive drum.
The Japanese Patent Application Laid-Open No. 59-211060 discloses means for handling paper jam that occurs in such a stand as described above, by sliding the part including the paper cassette and the take-up roller out of the stand. In accordance with using this means, the paper jam in the paper cassette or near the take-up roller can be removed at the outside of the stand. However, when paper jam occurs in the path between the intermediate rollers and the resist rollers, it is not possible in many cases to remove the jammed paper because most of the paper is held inside the copying machine, leaving no portion to grip for removal.
Further, the Japanese Utility Model Application Laid-Open No. 62-71640 discloses a paper feeding stand in which a support member for accommodating a detachable paper cassette is installed in such a way that it is movable in longitudinal directions with respect to the stand so as to facilitate the handling in case of paper jam.
In the above mentioned paper feeding stand, a cylindrically shaped positioning pin extending in the longitudinal direction is provided in the stand. On the other hand, a U-shaped recess that engages with the above positioning pin is provided in the support member.
Accordingly, when the support member with a paper cassette being attached is inserted into the stand, the recess engages with the positioning pin to fix the support member into position in the stand.
In the prior art technique as mentioned above, the support member is fixed in position in the vertical and longitudinal directions when pushed into the stand, since the positioning pin is of cylindrical shape. However, since the support member is not fixed in the lateral directions, another means is required for positioning in the lateral directions.
Therefore, this prior art has a disadvantage that it requires a larger number of parts, leading to higher cost of parts and assembling.
The applicant of the present invention already proposed paper feeding stands that are disclosed in the Japanese Utility Model Application No. 62-116189 and the Japanese Utility Model Application Laid-Open No. 62-71640.
In the paper feeding mechanism described in the above Utility Model Application No. 62-116189, the paper feeding unit is adjustable only in the lateral directions. Therefore, to make it adjustable in the twisting directions as well as in the lateral directions, another adjusting plate is required between the fixed side and the bottom plate, as described in the Utility Model Application Laid-Open No. 62-71640.
As mentioned above, in accordance with the prior art by the applicant, in order that the paper feeding unit is adjustable in the lateral directions and also in the twisting directions, additional parts are required.
Therefore the prior art either causes the difficulty in adjustment or leads to cost increase.
Furthermore, as disclosed in the Japanese Patent Publication No. 55-24110, a paper feeding unit is proposed in which a pair of rollers, one being convex and the other concave, are installed and paper is transported, being buckled between the rollers. This paper feeding unit is not equipped with a paper guide.
Another type of paper feeding unit that transports paper in a buckled state is disclosed in the Japanese Patent Publication No. 62-29352. This paper feeding unit also is not equipped with a paper guide between the rollers.
In the above mentioned paper feeding units, paper may slant while being transported because a paper guide is not provided between the pair of rollers.
Further, since the paper is forcibly held in a buckled state by the pair of rollers, the paper remains warped in a slightly buckled state, and if it is transported to the image forming part in this state, the problem arises that the image is not precisely transferred to the paper.
Generally, since such paper feeding stands take the weight of copying machines, the weight causes stress to the stands, which may hamper proper operation of the paper feeding mechanism and result in failure of operation. Deformation of the stand can be prevented by using stronger structural members, but this will increase the weight of the stand and decrease the operatability, and therefore, not desirable.